Lime slurry obtained by mixing quicklime or slaked lime and water is widely used for industrial purposes such as elimination of acidic gas and neutralization of wastewater. Moreover, use of slurry obtained by mixing fine particles of magnesium hydroxide, magnesium oxide, calcium hydroxide or the like with water as exhaust gas desulfurization adsorbent, wastewater neutralizer or the like is known. Further, methods of producing calcium carbonate of a desired crystal system showing superior physical properties as a paper coating material by using slaked lime slurry as a raw material are described in Japanese Patent Publication (KOKOKU) No. 55-51852 and Japanese Patent No. 2706384.
When slurry is produced by mixing fine particles of quicklime, slaked lime or the like and liquid such as water, a method of directly charging fine particles into a dissolution tank storing liquid such as water from an upper part of the tank is usually used. In this method, when fine particles are charged into the dissolution tank, fine particles fly and terribly spread around as dusts. Therefore, the dissolution tank is usually sealed, and a large size dust collecting filter apparatus is usually provided on the dissolution tank at the same time to aspirate the dusts and collecting them on a filter.
As described above, in the methods of directly charging fine particles, because of a large amount of producing dusts, a dust collecting filter apparatus of a large size is required, and at the same time, the filter is prone to cause choking, which requires frequent maintenance operations such as washing and exchange of the filter. Moreover, the methods also have a problem that aggregates of fine particles contact with and adhere to a sidewall of the dissolution tank without being completely dissolved or dispersed, and thus so-called scales are prone to be formed. A phenomenon that aggregates of fine particles that cannot be dissolved or dispersed remain in slurry to form floating aggregates is also likely to occur.
Japanese Patent Publication (KOKOKU) No. 5-35013 discloses a slurrying apparatus for preventing dusting upon charging of fine particles into water. This slurrying apparatus has a slurry storage tank and a slurrying tank storing water and connected to the slurry storage tank from the side thereof. In the slurrying tank, a fine particle feeding pipe is inserted from the water surface, and the end thereof reaches the neighborhood of the bottom. Fine particles are conveyed by the fine particle feeding pipe with being applied with pressure and injected into water from the end of the pipe. The fine particles are thereby mixed with water in the neighborhood of the bottom of the slurrying tank and thus slurried. As described above, this apparatus is characterized in that the dusting can be suppressed by mixing the fine particles and water at the bottom of water.